[deliverable/linux.git] / drivers / xen / xen-balloon.c

/******************************************************************************
 * Xen balloon driver - enables returning/claiming memory to/from Xen.
 *
 * Copyright (c) 2003, B Dragovic
 * Copyright (c) 2003-2004, M Williamson, K Fraser
 * Copyright (c) 2005 Dan M. Smith, IBM Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation; or, when distributed
 * separately from the Linux kernel or incorporated into other
 * software packages, subject to the following license:
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this source file (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sysdev.h>
#include <linux/capability.h>

#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/balloon.h>
#include <xen/xenbus.h>
#include <xen/features.h>
#include <xen/page.h>

#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))

#define BALLOON_CLASS_NAME "xen_memory"

static struct sys_device balloon_sysdev;

static int register_balloon(struct sys_device *sysdev);

static struct xenbus_watch target_watch =
{
	.node = "memory/target"
};

/* React to a change in the target key */
static void watch_target(struct xenbus_watch *watch,
			 const char **vec, unsigned int len)
{
	unsigned long long new_target;
	int err;

	err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
	if (err != 1) {
		/* This is ok (for domain0 at least) - so just return */
		return;
	}

	/* The given memory/target value is in KiB, so it needs converting to
	 * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
	 */
	balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
}

static int balloon_init_watcher(struct notifier_block *notifier,
				unsigned long event,
				void *data)
{
	int err;

	err = register_xenbus_watch(&target_watch);
	if (err)
		printk(KERN_ERR "Failed to set balloon watcher\n");

	return NOTIFY_DONE;
}

static struct notifier_block xenstore_notifier;

static int __init balloon_init(void)
{
	if (!xen_domain())
		return -ENODEV;

	pr_info("xen-balloon: Initialising balloon driver.\n");

	register_balloon(&balloon_sysdev);

	register_xen_selfballooning(&balloon_sysdev);

	target_watch.callback = watch_target;
	xenstore_notifier.notifier_call = balloon_init_watcher;

	register_xenstore_notifier(&xenstore_notifier);

	return 0;
}
subsys_initcall(balloon_init);

static void balloon_exit(void)
{
    /* XXX - release balloon here */
    return;
}

module_exit(balloon_exit);

#define BALLOON_SHOW(name, format, args...)				\
	static ssize_t show_##name(struct sys_device *dev,		\
				   struct sysdev_attribute *attr,	\
				   char *buf)				\
	{								\
		return sprintf(buf, format, ##args);			\
	}								\
	static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)

BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));

static SYSDEV_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
static SYSDEV_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
static SYSDEV_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);

static ssize_t show_target_kb(struct sys_device *dev, struct sysdev_attribute *attr,
			      char *buf)
{
	return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
}

static ssize_t store_target_kb(struct sys_device *dev,
			       struct sysdev_attribute *attr,
			       const char *buf,
			       size_t count)
{
	char *endchar;
	unsigned long long target_bytes;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;

	balloon_set_new_target(target_bytes >> PAGE_SHIFT);

	return count;
}

static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR,
		   show_target_kb, store_target_kb);


static ssize_t show_target(struct sys_device *dev, struct sysdev_attribute *attr,
			      char *buf)
{
	return sprintf(buf, "%llu\n",
		       (unsigned long long)balloon_stats.target_pages
		       << PAGE_SHIFT);
}

static ssize_t store_target(struct sys_device *dev,
			    struct sysdev_attribute *attr,
			    const char *buf,
			    size_t count)
{
	char *endchar;
	unsigned long long target_bytes;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	target_bytes = memparse(buf, &endchar);

	balloon_set_new_target(target_bytes >> PAGE_SHIFT);

	return count;
}

static SYSDEV_ATTR(target, S_IRUGO | S_IWUSR,
		   show_target, store_target);


static struct sysdev_attribute *balloon_attrs[] = {
	&attr_target_kb,
	&attr_target,
	&attr_schedule_delay.attr,
	&attr_max_schedule_delay.attr,
	&attr_retry_count.attr,
	&attr_max_retry_count.attr
};

static struct attribute *balloon_info_attrs[] = {
	&attr_current_kb.attr,
	&attr_low_kb.attr,
	&attr_high_kb.attr,
	NULL
};

static struct attribute_group balloon_info_group = {
	.name = "info",
	.attrs = balloon_info_attrs
};

static struct sysdev_class balloon_sysdev_class = {
	.name = BALLOON_CLASS_NAME
};

static int register_balloon(struct sys_device *sysdev)
{
	int i, error;

	error = sysdev_class_register(&balloon_sysdev_class);
	if (error)
		return error;

	sysdev->id = 0;
	sysdev->cls = &balloon_sysdev_class;

	error = sysdev_register(sysdev);
	if (error) {
		sysdev_class_unregister(&balloon_sysdev_class);
		return error;
	}

	for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
		error = sysdev_create_file(sysdev, balloon_attrs[i]);
		if (error)
			goto fail;
	}

	error = sysfs_create_group(&sysdev->kobj, &balloon_info_group);
	if (error)
		goto fail;

	return 0;

 fail:
	while (--i >= 0)
		sysdev_remove_file(sysdev, balloon_attrs[i]);
	sysdev_unregister(sysdev);
	sysdev_class_unregister(&balloon_sysdev_class);
	return error;
}

MODULE_LICENSE("GPL");
Commit	Line	Data
803eb047 DDG	1	/******************************************************************************
	2	* Xen balloon driver - enables returning/claiming memory to/from Xen.
	3	*
	4	* Copyright (c) 2003, B Dragovic
	5	* Copyright (c) 2003-2004, M Williamson, K Fraser
	6	* Copyright (c) 2005 Dan M. Smith, IBM Corporation
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License version 2
	10	* as published by the Free Software Foundation; or, when distributed
	11	* separately from the Linux kernel or incorporated into other
	12	* software packages, subject to the following license:
	13	*
	14	* Permission is hereby granted, free of charge, to any person obtaining a copy
	15	* of this source file (the "Software"), to deal in the Software without
	16	* restriction, including without limitation the rights to use, copy, modify,
	17	* merge, publish, distribute, sublicense, and/or sell copies of the Software,
	18	* and to permit persons to whom the Software is furnished to do so, subject to
	19	* the following conditions:
	20	*
	21	* The above copyright notice and this permission notice shall be included in
	22	* all copies or substantial portions of the Software.
	23	*
	24	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	25	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	26	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	27	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	28	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	29	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
	30	* IN THE SOFTWARE.
	31	*/
	32
	33	#include <linux/kernel.h>
	34	#include <linux/module.h>
	35	#include <linux/sysdev.h>
	36	#include <linux/capability.h>
	37
	38	#include <xen/xen.h>
	39	#include <xen/interface/xen.h>
	40	#include <xen/balloon.h>
	41	#include <xen/xenbus.h>
	42	#include <xen/features.h>
	43	#include <xen/page.h>
	44
	45	#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
	46
	47	#define BALLOON_CLASS_NAME "xen_memory"
	48
	49	static struct sys_device balloon_sysdev;
	50
	51	static int register_balloon(struct sys_device *sysdev);
	52
	53	static struct xenbus_watch target_watch =
	54	{
	55	.node = "memory/target"
	56	};
	57
	58	/* React to a change in the target key */
	59	static void watch_target(struct xenbus_watch *watch,
	60	const char **vec, unsigned int len)
	61	{
	62	unsigned long long new_target;
	63	int err;
	64
65	err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
66	if (err != 1) {
67	/* This is ok (for domain0 at least) - so just return */
68	return;
69	}
70
71	/* The given memory/target value is in KiB, so it needs converting to
72	* pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
73	*/
74	balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
75	}
76
77	static int balloon_init_watcher(struct notifier_block *notifier,
78	unsigned long event,
79	void *data)
80	{
81	int err;
82
83	err = register_xenbus_watch(&target_watch);
84	if (err)
85	printk(KERN_ERR "Failed to set balloon watcher\n");
86
87	return NOTIFY_DONE;
88	}
89
90	static struct notifier_block xenstore_notifier;
91
92	static int __init balloon_init(void)
93	{
94	if (!xen_domain())
95	return -ENODEV;
96
97	pr_info("xen-balloon: Initialising balloon driver.\n");
98
99	register_balloon(&balloon_sysdev);
100
a50777c7 DM	101	register_xen_selfballooning(&balloon_sysdev);
a50777c7 DM	102
803eb047 DDG	103	target_watch.callback = watch_target;
	104	xenstore_notifier.notifier_call = balloon_init_watcher;
	105
	106	register_xenstore_notifier(&xenstore_notifier);
	107
	108	return 0;
	109	}
	110	subsys_initcall(balloon_init);
	111
	112	static void balloon_exit(void)
	113	{
	114	/* XXX - release balloon here */
	115	return;
	116	}
	117
	118	module_exit(balloon_exit);
	119
	120	#define BALLOON_SHOW(name, format, args...) \
	121	static ssize_t show_##name(struct sys_device *dev, \
	122	struct sysdev_attribute *attr, \
	123	char *buf) \
	124	{ \
	125	return sprintf(buf, format, ##args); \
	126	} \
	127	static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
	128
	129	BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
	130	BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
	131	BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
	132
	133	static SYSDEV_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
	134	static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
	135	static SYSDEV_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
	136	static SYSDEV_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
	137
	138	static ssize_t show_target_kb(struct sys_device dev, struct sysdev_attribute attr,
	139	char *buf)
	140	{
	141	return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
	142	}
	143
	144	static ssize_t store_target_kb(struct sys_device *dev,
	145	struct sysdev_attribute *attr,
	146	const char *buf,
	147	size_t count)
	148	{
	149	char *endchar;
	150	unsigned long long target_bytes;
	151
	152	if (!capable(CAP_SYS_ADMIN))
	153	return -EPERM;
	154
	155	target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
	156
	157	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
	158
	159	return count;
	160	}
	161
	162	static SYSDEV_ATTR(target_kb, S_IRUGO \| S_IWUSR,
	163	show_target_kb, store_target_kb);
	164
	165
	166	static ssize_t show_target(struct sys_device dev, struct sysdev_attribute attr,
167	char *buf)
168	{
169	return sprintf(buf, "%llu\n",
170	(unsigned long long)balloon_stats.target_pages
171	<< PAGE_SHIFT);
172	}
173
174	static ssize_t store_target(struct sys_device *dev,
175	struct sysdev_attribute *attr,
176	const char *buf,
177	size_t count)
178	{
179	char *endchar;
180	unsigned long long target_bytes;
181
182	if (!capable(CAP_SYS_ADMIN))
183	return -EPERM;
184
185	target_bytes = memparse(buf, &endchar);
186
187	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
188
189	return count;
190	}
191
192	static SYSDEV_ATTR(target, S_IRUGO \| S_IWUSR,
193	show_target, store_target);
194
195
196	static struct sysdev_attribute *balloon_attrs[] = {
197	&attr_target_kb,
198	&attr_target,
199	&attr_schedule_delay.attr,
200	&attr_max_schedule_delay.attr,
201	&attr_retry_count.attr,
202	&attr_max_retry_count.attr
203	};
204
205	static struct attribute *balloon_info_attrs[] = {
206	&attr_current_kb.attr,
207	&attr_low_kb.attr,
208	&attr_high_kb.attr,
209	NULL
210	};
211
212	static struct attribute_group balloon_info_group = {
213	.name = "info",
214	.attrs = balloon_info_attrs
215	};
216
217	static struct sysdev_class balloon_sysdev_class = {
218	.name = BALLOON_CLASS_NAME
219	};
220
221	static int register_balloon(struct sys_device *sysdev)
222	{
223	int i, error;
224
225	error = sysdev_class_register(&balloon_sysdev_class);
226	if (error)
227	return error;
228
229	sysdev->id = 0;
230	sysdev->cls = &balloon_sysdev_class;
231
232	error = sysdev_register(sysdev);
233	if (error) {
234	sysdev_class_unregister(&balloon_sysdev_class);
235	return error;
236	}
237
238	for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
239	error = sysdev_create_file(sysdev, balloon_attrs[i]);
240	if (error)
241	goto fail;
242	}
243
244	error = sysfs_create_group(&sysdev->kobj, &balloon_info_group);
245	if (error)
246	goto fail;
247
248	return 0;
249
250	fail:
251	while (--i >= 0)
252	sysdev_remove_file(sysdev, balloon_attrs[i]);
253	sysdev_unregister(sysdev);
254	sysdev_class_unregister(&balloon_sysdev_class);
255	return error;
256	}
257
258	MODULE_LICENSE("GPL");